Cancer Epidemiology Centre, Cancer Council Victoria, Melbourne, Australia.
Cancer Epidemiol Biomarkers Prev. 2013 Aug;22(8):1409-16. doi: 10.1158/1055-9965.EPI-13-0136. Epub 2013 May 29.
Adult weight is positively associated with postmenopausal breast cancer but few studies have investigated whether there are associations with weight and body mass index (BMI) in early adulthood, or subsequent weight change.
A total of 14,441 postmenopausal women from the Melbourne Collaborative Cohort Study (MCCS) were followed for 16.5 years (mean) and 668 incident breast cancers were identified. Hazard ratios (HRs) were estimated using Cox regression.
Weight and BMI at 18 to 21 years were not associated with risk of any type of breast cancer and there was no variation by age. Women with the greatest increase in weight and BMI had higher risk at older ages [HR per 5 kg/m(2) gain in BMI = 1.24; 95% confidence interval (CI), 1.11-1.40], although the test for homogeneity by age was not significant. At older ages, the association was stronger for progesterone (PR) positive disease compared with PR negative disease (HR per 5 kg/m(2) gain in BMI, 1.43; 95% CI, 1.23-1.66; test for homogeneity by PR status, P < 0.01) and for diseases that were positive for both estrogen (ER) and PR (HR per 5 kg/m(2) gain in BMI, 1.45; 95% CI, 1.24-1.69; test for homogeneity by ER/PR status, P = 0.02). HRs were also greater for HER2- and luminal A tumors, but the P values for homogeneity by tumor subgroups were not significant.
Early adulthood weight is not associated with risk of postmenopausal breast cancer. Greater weight gain during adulthood might be associated with increased risk for older women (>69 years) and this association might vary by tumor hormone receptor status.
Further studies need to investigate the impact of increase in weight during adulthood on postmenopausal breast cancer risk and the potential variation by age or tumor characteristics.
成人的体重与绝经后乳腺癌呈正相关，但很少有研究调查过年轻时的体重和体重指数（BMI）以及随后的体重变化是否与乳腺癌有关。
共有 14441 名来自墨尔本协作队列研究（MCCS）的绝经后妇女参与了这项研究，随访时间为 16.5 年（平均），期间共发现 668 例乳腺癌病例。使用 Cox 回归估计风险比（HR）。
18 至 21 岁时的体重和 BMI 与任何类型乳腺癌的风险无关，且与年龄无关。体重和 BMI 增加最多的女性在年龄较大时风险更高[每增加 5kg/m2 BMI 的 HR 为 1.24；95%置信区间（CI）为 1.11-1.40]，尽管年龄的同质性检验不显著。在年龄较大时，这种相关性在孕激素受体（PR）阳性疾病中比在 PR 阴性疾病中更强（每增加 5kg/m2 BMI 的 HR 为 1.43；95%CI 为 1.23-1.66；PR 状态的同质性检验，P<0.01），并且在雌激素受体（ER）和 PR 均为阳性的疾病中更强（每增加 5kg/m2 BMI 的 HR 为 1.45；95%CI 为 1.24-1.69；ER/PR 状态的同质性检验，P=0.02）。HER2-和 luminal A 肿瘤的 HR 也更高，但肿瘤亚组的同质性检验 P 值不显著。
年轻时的体重与绝经后乳腺癌的风险无关。成年后体重增加较多可能与年龄较大的女性（>69 岁）的风险增加有关，这种关联可能因肿瘤激素受体状态而异。
需要进一步研究成年后体重增加对绝经后乳腺癌风险的影响，以及年龄或肿瘤特征的潜在变化。
